Tuesday, June 17, 2008

One comment I hear a lot in discussions about atheism is that Dawkins (who apparently is the One True Atheist) is very simplistic in his approach to religion. This is semi-true - his book The God Delusion does indeed go lightly the "sophisticated" theology.

However, this seems vastly more acceptable when you realise that very few of the folks at whom his book is aimed will have Plantinga's works on their bedside table. In fact, they're rather more likely to be familiar with crap like this.

Given this, can I say once and for all that, despite not discussing the evolutionary transcendental argument in much depth, Dawkins' book is a fine piece of work that is generally appropriate to the audience for whom it was intended.
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Thursday, June 12, 2008

One of the things that Linux doesn't do too well at is dealing with the bizarre obfuscations that many media companies use to protect their content. For example, I just came across an interesting-sounding movie called "The Fall". Now, you'd have thought that a trailer, at least, would be easy to find and view. Sadly not.

Step 1: Attempt to view a Flash trailer. Fail. It appears that something in the Flash code is sufficiently weird that Gnash (the open-source Flash viewer) can't handle it.Blame: partly on open source, partly on whoever wrote the code.

Step 2: Look up the trailer on Apple's trailer site. Find that the page requires some kind of Quicktime plugin, which isn't available for Linux. Blame: mostly on Apple.

Step 3: Download the trailer directly. Discover that the URL actually leads to some kind of 138-byte redirector file. There is no apparent reason for this - I can only assume that it's intended to stop people downloading the trailer rather than streaming (why???). Blame: Apple.

Step 4: Look at the redirector's bytecode, and find the trailer address embedded in it. Guess the URL, download the trailer and watch it as nature intended. For Pete's sake, people, if you're going to obfuscate then a useful tactic would be to NOT PUT THE FILENAME AS PLAINTEXT IN THE OBFUSCATOR!!! What the hell are these people smoking?

Verdict: Apart from the Flash thing, non-Microsoft users like myself would be fine if it wasn't for the IDIOT COMPANIES who apply COMPLETELY POINTLESS "PROTECTION" to their oh-so-valuable film trailers. Gah.
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Sunday, June 01, 2008

A while back, I mentioned that I'd hopefully be doing some trials with a friend who claims the existence of psychic powers etc. Yesterday we finally got round to doing some preliminaries.

The tests will be a lot less complex than I'd expected because, rather than testing for psychic communication between two believers (my friend and a third party), we're going to test his ability to channel energy through a pendulum into my hand. It'll be a straightforward "which hand am I holding the pendulum over" thing.

Protocol 1 (non-rigorous tomfoolery)

Our initial experiments were not terribly promising. I thought I could feel something the first time we did it, and guessed correctly. So far so good. However, I suspected that the "something" I could feel was in fact heat off my friend's hand, so for the second and third runs I covered each of my hands with a sheet of paper. I got both wrong.

Protocol 2 (slightly more rigorous)

At this point, my friend commented that, when he'd been mucking about with a fellow believer, the first run in any given sequence had generally been the most successful. He speculated that, after that point, there was some kind of psychic residue contaminating the experiment that took a while to wear off.

To eliminate this factor, we arranged a new protocol: every time we see each other (about once a week), we'll repeat the test once. For the moment, the only specific precaution against bias will be closed eyes and paper-covered hands. After five runs, we'll check the tally of results to see whether there's any statistically significant effect. If there is, we'll up the rigour. If not, we'll investigate other test options.

PS. To my friend's credit, he didn't use the "psychic residue" as an excuse for failure. In fact I had to persuade him not to include the initial negative results in the final tally.

What is a statistically significant effect?

The basic approach used for statistical testing is "significance levels". If something is "significant at the 5% level", that means that the chances of getting a false positive (an apparently significant result that appeared by accident) are 5%.

If there is no psychic effect then, over five trials, the probabilities of success are as follows:

If we wanted to do a significance test at the 20% level, we would say that the result were significant if 4 or 5 successes appeared (since P(5)+P(4) < 20% < P(5)+P(4)+P(3)). This is a pretty damn easy hurdle to pass, so if we don't get 4 successes then there's probably not much point carrying on with this protocol.

If we wanted to do a success at the 5% level, we would say that the results were significant if 5 successes appeared (since P(5) < 20% < P(5)+P(4)). This is a slightly tougher hurdle - if we pass it (e.g. if we have 100% success rate) then it'll be worth applying stronger controls.